[R] difference between 2 ecdfs

[David Winsemius]

In article 
<0FF736F1E306A446A88FD41FDDDC10AF1C77B0 at BWPW05.f2.enterprise>,
 <Erwann.Rogard at sanofi-aventis.com> wrote:

> hi,
>  
> a) i have something like:
>  
> ecdfgrp1<-ecdf(subset(mydata,TMT_GRP==1)$Y);
> 
> ecdfgrp2<-ecdf(subset(mydata,TMT_GRP==2)$Y);
> 
> how can i plot the difference between these 2 step functions?
>  
> i could begin with ecdfrefl<-function(x){ecdfgrp2(x)-ecdfgrp1(x);} ...
> what next?
>  
#not tested  ...mydata not provided

ecrange<-range(mydata$Y)

plot(ecdfrefl(seq(from=ecrange[1],to=ecrange[2],by=0.2))


> b) if i have a vector with repeated numeric values how can i get the
> subset without repeated values .e.g (0,4,0,2,2) ----> (0,4,2) ?
>  

?unique

> ttt<-c(1,3,5,5,5,7)
> unique(ttt)
[1] 1 3 5 7

-- 
David Winsemius